Gamma-ray Burst 980706

A bright (peak count rate about 32000 cts/s) and short Gamma-Ray Burst (BATSE trigger No. 6904) was detected with BATSE and COMPTEL on July 6, 1998 at 15:59:47 UT. Detection by Ulysses has allowed a triangulation. RXTE has scanned the 8 by 4 deg. error box between 18:39-20:45 UT.
The GRB consisted of a single spike of less than 1 sec duration. There is a small exponential decay for 5-10 sec after the spike. This burst was seen above 300 keV. (all information courtesy of the instrument teams)

Previous IAU Circulars

• none yet

• COMPTEL position

  *****************************************************
  BURST_DATE : 11000 TJD; 06-Jul-1998
  BURST_TIME : 57587.00 sec; 15:59:47.00 UT
  -----------------------------------------------------
  BURST_SCZEN:  46.72 deg     {OScan=  22.30}
  BURST_SCAZI:  67.28 deg     {XScan= -42.19}
  BURST_CLASS: WEAK    (Approx   23 events)
  BURST_DETEC: MEDIUM  (Approx  6.9 sigma)
  *****************************************************
  COORD_J2000: [RAsc       Decl] [RAsc            Decl]
  ============ ================= ======================
  MAXPOS_J20 : [161.52d  57.49d] [10h46m05s  57d29'33"]
  -----------------------------------------------------
  ERRBOX1_J20: [158.22d  58.14d] [10h32m53s  58d08'31"]
  ERRBOX2_J20: [158.62d  56.28d] [10h34m29s  56d16'50"]
  ERRBOX3_J20: [165.95d  56.52d] [11h03m48s  56d31'12"]
  ERRBOX4_J20: [165.93d  58.39d] [11h03m44s  58d23'37"]
  *****************************************************
  COORD_B1950: [RAsc       Decl] [RAsc            Decl]
  ============ ================= ======================
  MAXPOS_B50 : [160.76d  57.77d] [10h43m03s  57d46'02"]
  -----------------------------------------------------
  ERRBOX1_B50: [157.44d  58.41d] [10h29m45s  58d24'39"]
  ERRBOX2_B50: [157.85d  56.55d] [10h31m24s  56d33'00"]
  ERRBOX3_B50: [165.23d  56.80d] [11h00m56s  56d48'04"]
  ERRBOX4_B50: [165.21d  58.67d] [11h00m50s  58d40'29"]
  -----------------------------------------------------
  NOTE01-----: Error box indicates 2-sigma statistical
  NOTE02-----: confidence limits only.

• GCN notice #129
  K. Hurley, on behalf of the Ulysses GRB team, and C. Kouveliotou, on behalf of the BATSE team, report: We have obtained a refined, but still preliminary IPN annulus for this burst (BATSE #6904). The annulus center is located at (J2000) R.A.=151.981, Decl.=8.780. Its radius is 49.641 +/- 0.026 degrees. A map showing the BATSE, COMPTEL, and IPN locations may be found at http://ssl.berkeley.edu/ipn3/980706 and is shown below.
  
• GCN notice #138
  F. E. Marshall (NASA/GSFC) and T. Takeshima (USRA/GSFC), on behalf of the RXTE team, and P. Woods (UAH/MSFC) on behalf of the BATSE team, report the detection of an X-ray source during scans of the Locburst error region for GRB 980706 (BATSE trigger 6904) with the PCA on RXTE. A 4x8 degree region centered on RA=161.82 and DEC=57.52 was scanned during a 2-hour interval starting July 6.781, which is 2.7 hours after the burst. A 90% confidence error region for the source has corners at (RA, DEC) of (165.586, 57.801), (164.897, 55.836), (164.366, 55.890), and (164.993, 57.860). Since this error box intersects the preliminary IPN annulus (GCN Circ. 129), the X-ray source may be the afterglow of the GRB. If so, the afterglow had a flux of about 2 mCrab in the 2-10 keV band 2.9 hours after the burst. The intersection of the error box and the preliminary IPN annulus is centered at (165.137, 57.385),and has a width of about 0.6 deg. in RA and 0.026 deg. in DEC. However, the X-ray source was not detected during two subsequent scans 1.5 hours later indicating either unusual variability (a decay index of at least 3 for an assumed power-law decay) or that the X-ray source is not located in the intersection of the error box and the annulus. The ROSAT-survey source J105825.9+564716, which lies just outside the X-ray error box, is an alternative identification of the X-ray source. In this case, the X-ray source is unrelated to the GRB.
• COMPTEL updated position
  

  TITLE:              GCN/GRO_COMPTEL BURST POSITION NOTICE
  NOTICE_DATE:        Thu 09 Jul 98 22:28:48 UT
  NOTICE_TYPE:        GRO-COMPTEL Update
  TRIGGER_NUM:        6904
  GRB_DATE:           11000 TJD;   187 DOY;   98/07/06
  GRB_TIME:           57587.00 SOD {15:59:47.00} UT
  GRB_COMPTEL_RA:     161.32d {+10h 45m 17s} (J2000),
                      161.30d {+10h 45m 11s} (current),
                      160.53d {+10h 42m 08s} (1950)
  GRB_COMPTEL_DEC:    +57.71d {+57d 42' 36"} (J2000),
                      +57.72d {+57d 43' 04"} (current),
                      +57.97d {+57d 58' 23"} (1950)
  GRB_ERROR_RA1:      151.97d {+10h 07m 53s} (J2000)
  GRB_ERROR_DEC1:      58.56d {+58d 33' 36"} (J2000)
  GRB_ERROR_RA2:      153.16d {+10h 12m 38s} (J2000)
  GRB_ERROR_DEC2:      55.30d {+55d 17' 60"} (J2000)
  GRB_ERROR_RA3:      167.64d {+11h 10m 34s} (J2000)
  GRB_ERROR_DEC3:      55.98d {+55d 58' 48"} (J2000)
  GRB_ERROR_RA4:      167.79d {+11h 11m 10s} (J2000)
  GRB_ERROR_DEC4:      59.32d {+59d 19' 12"} (J2000)
  GRB_COMPTEL_INTEN:  23 [events]
  GRB_COMPTEL_SIGNIF: 7.0 [sigma]
  SUN_POSTN:          105.61d {+07h 02m 27s}  +22.66d {+22d 39' 47"}
  SUN_DIST:            52.87 [deg]
  MOON_POSTN:         247.67d {+16h 30m 41s}  -16.71d {-16d 42' 39"}
  MOON_DIST:          102.17 [deg]
  PROG_VERSION:       13.00
  COMMENTS:           GRO-COMPTEL GRB location.  
  COMMENTS:           Error box indicates 2-sigma statistical  
  COMMENTS:           confidence limits only.
  COMMENTS:           *****************************************************  
  COMMENTS:           Burst location uncertainty contour (2-sigma) follows.  
  COMMENTS:           50 contour points, J2000 coordinates in deg  
  COMMENTS:           IP    RAsc    Decl      IP    RAsc    Decl  
  COMMENTS:           -----------------------------------------------------  
  COMMENTS:           01   159.45   59.16     26   160.19   55.87  
  COMMENTS:           02   158.36   59.06     27   161.30   55.90  
  COMMENTS:           03   157.28   58.92     28   162.20   55.99  
  COMMENTS:           04   156.22   58.77     29   163.11   56.04  
  COMMENTS:           05   155.22   58.54     30   164.01   56.13  
  COMMENTS:           06   154.70   58.41     31   164.88   56.30  
  COMMENTS:           07   154.20   58.25     32   165.79   56.48  
  COMMENTS:           08   153.73   58.08     33   166.20   56.62  
  COMMENTS:           09   153.28   57.89     34   166.57   56.78  
  COMMENTS:           10   152.91   57.64     35   166.96   56.95  
  COMMENTS:           11   152.82   57.49     36   167.32   57.14
  COMMENTS:           12   152.86   57.33     37   167.59   57.37  
  COMMENTS:           13   152.87   57.17     38   167.70   57.64  
  COMMENTS:           14   152.77   57.03     39   167.71   57.80  
  COMMENTS:           15   152.67   56.73     40   167.58   57.95  
  COMMENTS:           16   153.07   56.49     41   167.23   58.22  
  COMMENTS:           17   153.59   56.34     42   166.77   58.42  
  COMMENTS:           18   154.10   56.20     43   166.24   58.59  
  COMMENTS:           19   154.65   56.09     44   165.71   58.71  
  COMMENTS:           20   155.19   56.01     45   165.15   58.81  
  COMMENTS:           21   155.76   55.97     46   164.58   58.90  
  COMMENTS:           22   156.32   55.93     47   164.00   58.96  
  COMMENTS:           23   156.88   55.88     48   162.89   59.11  
  COMMENTS:           24   157.98   55.84     49   161.75   59.17  
  COMMENTS:           25   159.09   55.81     50   160.60   59.16